[_Codemonkeyism]

Somehow doesn't work for me :-(

[todd8]

U2F is by default disabled in Firefox. You have to turn it on before using your Yubico (or other FIDO) key for a service being accessed though Firefox. It’s easy to enable. See https://www.trishtech.com/2018/07/enable-fido-u2f-security-k...

[_Codemonkeyism]

Did that some time ago already, doesn't work for me, I can't log in with my Yubikey, which at the same time works from Chrome.

[todd8]

Oh sorry it wasn't something simple. I just enabled it on my laptop yesterday and it worked (Firefox 62.0.2 running on MacOS 10.14).

At first I thought that I hadn't enabled right. After checking the setting again, I found the problem--I had plugged the Yubico Key in upside-down.